This invention relates to a folding frame of the type useful as a support mechanism for wheelchairs. More particularly, the invention pertains to a chair or wheelchair frame that can be easily folded to a compact size for storage or transportation.
Wheelchairs are well known forms of transportation that increase the mobility of the physically impaired. Wheelchairs are typically relatively small, single-person conveyances that generally comprise a seat supported by a frame which, in turn, is supported by two opposed drive wheels and two front casters. Many manual wheelchairs are designed so that they can be folded for more convenient storage when not in use. Typical folding mechanisms involve cross braces extending from an upper part of one side frame to a lower part of another side frame. The cross braces are often provided in a tubular form in a telescoping arrangement to allow the tubular cross braces to slide within each other during folding, and to allow adjustment of the length of the cross braces for width and height adjustment of the wheelchair when unfolded.
In U.S. Pat. No. 4,595,212 there is illustrated a wheelchair folding mechanism having upper and lower spacer members that pivot when a central folding frame is moved forward with respect to the side frames of the wheelchair.
In U.S. Pat. No. 4,595,212 there is illustrated a wheelchair folding mechanism having upper and lower spacer members that pivot when a central folding frame is moved forward with respect to the side frames of the wheelchair.
Despite the benefits of known folding wheelchair mechanisms, it would be advantageous if there could be developed a wheelchair folding mechanism that not only folds into a compact space, but also enables the frame to be opened into any one of several different widths as desired to fit the needs of the wheelchair user.
The above objects as well as other objects not specifically enumerated are achieved by a wheelchair frame having first and second side frames, a slider housing, and a slider member mounted for movement relative to the slider housing. Links connect the slider housing to both the first and second side frames, and links connect the slider member to both the first and second side frame side frames. Movement of the slider member relative to the slider housing actuates the links to change the spacing between the first and second side frames, thereby opening and closing the wheelchair frame.
According to this invention, there is also provided a wheelchair frame including first and second side frames, a slider housing, and a slider member mounted for movement relative to the slider housing. Links connect the slider housing to both the first and second side frames, and links connect the slider member to both the first and second side frame side frames. A stop in the form of a pin for limits the extent to which the slider member can be moved with respect to the slider housing, thereby establishing a minimum and maximum width of the wheelchair frame. The stop is seated in an orifice that is adjustable to any one of several predetermined locations on the slider member, with each of the locations corresponding to a different width of the wheelchair frame when the wheelchair frame is opened. Movement of the slider member relative to the slider housing actuates the links to change the spacing between the first and second side frames, thereby opening and closing the wheelchair frame.
According to this invention, there is also provided a wheelchair frame including first and second side frames, a slider housing, and a slider member mounted for movement relative to the slide housing. Links connect the slider housing and the slider member to both the first and second side frames. A biasing member connects the slider housing and the slider member. The biasing member biases the slider housing and slider member toward each other. Actuation of the links changes the spacing between the first and second side frames, thereby opening and closing the wheelchair frame, with the biasing member acting to open the wheelchair frame.
According to this invention, there is also provided a wheelchair frame including first and second side frames, and a slider positioned between the side frames. The slider is mounted for movement in forward and rearward directions with respect to the side frames. Eight links connect the slider to both the side frames so that movement of the slider relative to the side frames changes the spacing between the side frames, thereby opening and closing the wheelchair frame. Four of the links are positioned in four different horizontal planes on the right side of the wheelchair, and the other four of the links are mounted in four different horizontal planes on the left side of the wheelchair.
According to this invention, there is also provided a wheelchair frame including first and second side frames, and a slider positioned between the side frames. The slider is mounted for movement in forward and rearward directions with respect to the side frames. Links connect the slider to both the side frames so that movement of the slider relative to the side frames changes the spacing between the side frames, thereby opening and closing the wheelchair frame. A biasing member is connected to the slider. The biasing member biases the slider in a direction to open the wheelchair frame.
According to this invention there is also provided a wheelchair frame that includes first and second side frames, and a slider positioned between the side frames, the slider being mounted for movement in forward and rearward directions with respect to the side frames. Links connect the slider to both the side frames so that movement of the slider relative to the side frames changes the spacing between the side frames, thereby opening and closing the wheelchair frame. At least three links are positioned in separate horizontal planes on the right side of the wheelchair, and at least three links are mounted in separate horizontal planes on the left side of the wheelchair.
According to this invention there is also provided a wheelchair frame that has first and second side frames, and a slider positioned between the side frames, the slider being mounted for movement in forward and rearward directions with respect to the side frames. Links connect the slider to both the side frames so that movement of the slider relative to the side frames changes the spacing between the side frames, thereby opening and closing the wheelchair frame. A biasing member is connected to the slider. The biasing member biases the slider in a direction to open the wheelchair frame.
According to this invention there is also provided a wheelchair that is foldable to open and closed positions. The wheelchair includes first and second frame members that are movable with respect to each other during folding of the wheelchair. A biasing member is connected to at least one of the frame members. Movement of the frame members with respect to each other during folding of the wheelchair creates a biasing force in the biasing member urging the wheelchair to an open position.
According to this invention there is also provided a wheelchair that is foldable to open and closed positions. The wheelchair includes first and second frame members that are movable with respect to each other during folding and unfolding of the wheelchair. A handle is connected to the first frame member and mounted so that when the first frame member is urged upwardly by the handle, the second frame member is moved apart from the first frame member by the weight of the wheelchair. A biasing member is connected between the first and second frame members. Movement of the frame members apart from each other during folding of the wheelchair creates a biasing force in the biasing member urging the wheelchair to an open position.
Various objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiments, when read in light of the accompanying drawings.